The present study explores the approaches employed by sixth-grade students to compare rival solutions in socio-scientific decision-making situations. Data were collected using three specially developed open-ended tasks. Two of them were administered to 96 students in a written form while the third was administered to 20 of these students through individual follow-up interviews. Our findings suggest that students failed to consistently apply coherent decision-making approaches. Instead, they employed a diversity of approaches ranging from non-compensatory strategies that avoided tradeoffs between advantages and disadvantages of rival solutions, to strategies that sought to synthesize these two aspects, though in an invalid manner. We demonstrate that these strategies are the outcome of a number of prevalent reasoning difficulties. (Contains 3 figures and 5 tables.)